Conventional printing devices generally include one or more ink tanks that store ink and supply it to a printhead such as a thermal inkjet printhead. By way of example, inkjet printing is a conventional technique by which printing is normally accomplished without contact between the printing apparatus and the substrate, or medium, on which the desired print characters are deposited. Conventional inkjet printing devices such as a fax, printer, photo printer, all-in-one device, plotter, or any other device incorporating inkjet printing technology typically include one or more ink tanks in which ink is stored and supplies ink from the tank to one or more inkjet printheads, which dispense the ink for printing. In one embodiment of the inkjet printing device, the ink tank and printhead are generally placed within a movable print carriage of the inkjet device. In another embodiment, the ink tank is fixedly connected to the inkjet device while the printhead is connected to the movable print carriage. In still another embodiment of the inkjet printing device, both the printhead and ink tank are combined into single unit print cartridge connected to a movable carriage.
Due to conventional ink tank designs, such tanks can provide very inconsistent ink pressure to the inkjet printhead, which can cause high variability in the ink jetting operation. This high variability in the ink jetting operation can create high variability in the print quality of the final product, which is very undesirable. Another opportunity for improvement with conventional ink tanks is the depriming of the printhead, which can cause the printhead to fail. This can occur if printing continues after the ink tank has been emptied of all its ink.
Accordingly, there is a need for an improved ink tank.